docs: def delete_subtrie(self, key):
          """
          Given a key prefix, delete the whole subtrie that starts with the key prefix.
  
          Key will be encoded into binary array format first.
  
          It will call `_set` with `if_delete_subtrie` set to True.
          """
          validate_is_bytes(key)
  
          self.root_hash = self._set(
              self.root_hash,
              encode_to_bin(key),
              value=b'',
              if_delete_subtrie=True,
          )